1. Field of the Invention
The present invention relates to a recycling plastic parts used in a lens-fitted photo film unit, more particularly to the lens-fitted photo film unit using reproduction plastic parts and its manufacturing method. Hereinafter the lens-fitted photo film unit is referred to as a film unit.
2. Explanations of the Prior Arts
Recently, in order to preserve the environment and reduce the industrial waste, industrial products have been widely recycled. In case of the industrial products with many parts, recycling by each parts is more efficient than recycling products altogether. There are two kinds of parts recycling: reuse and restoring into materials.
The recycling of a film unit is described in detail in Japanese Laid-open Patent Application No. 6-161042. In the photofinishing laboratory, a film cartridge is taken out of the used film unit for photo print processing. The vacant film unit is collected by a manufacturer and is disassembled into parts on the recycling line by the manufacturer. Firstly, a label is removed from the vacant film unit, separating the label from a unit body. Next, the unit body is separated into a body section, a front cover and a rear cover. And finally the body section is separated into a taking lens, an exposure unit, a flash unit and so forth, leaving a plastic body base.
The taking lens, the exposure unit and the flash unit are inspected after cleaning process. The normal ones are sent to the manufacturing line in order to use as parts for a new product. Such plastic parts as the front cover, the rear cover, the body base and so forth are used as plastic materials.
Generally, the used plastic parts are crushed. The crushed materials, which are used as plastic material, are supplied to a plastic-forming machine for forming reproduction plastic parts. In case the crushed materials are used, heat on forming does not completely melt the crushed materials, leaving masses as like little grains on the reproduction plastic parts.
When the masses appear on the surface of the reproduction plastic parts, it presses a photo film to occur pressure marks and scratches on the photo film. In the field of a film unit recycling, the fact was well known that it was impossible to use the crushed materials as plastic materials to prevent from the pressure marks and scratches on the photo film.
For this reason, the crushed materials are processed recycled pellets, which are made as follows: Firstly the crushed materials are melted and formed into strand-formed primary materials by a molding and extruding machine. Secondly, the primary materials are cut at a regular length to recycled pellets. By using the recycled pellets as plastic materials, the reproduction plastic parts are formed by the plastic-forming machine. A manufacturing cost is high in this recycling method because the recycled pellets need to be processed. Since the film unit is characterized by its low cost, manufacturing cost in the reproduction plastic parts gives rise to a serious problem.
The main object of the present invention is to provide a lens-fitted photo film unit and its manufacturing method for reducing the recycling cost.
Another object of the present invention is to provide a lens-fitted photo film unit and its manufacturing method that make good use of reproduction plastic parts that might have small masses of crushed materials on its surface.
The above object and other objects are achieved by using the reproduction plastic parts, which are made of crushed materials of used plastic parts, where they are not in contact with a photo film such as a front cover. The crushed materials are used as a whole or a part of the plastic materials.
According to a preferred embodiment of the present invention, the crushed materials are not used for parts such as a body base and a rear cover that are in contact with the photo film, but the reproduction plastic parts made of recycled pellets are used. The recycled pellets are used all as plastic materials or mixed with new pure pellets.
According to the present invention, the reproduction plastic parts made of the crushed materials are used for the plastic parts which do not produce pressure marks and scratches. Consequently, the manufacturing cost for the film unit can be lowered.